99_timing.sh

#!/bin/sh

gettimeofday() {
	date '+%s%N'
}

bash_timing() {
	local LANG=C rc=$?
	if [ "$BASH_COMMAND" == "$PROMPT_COMMAND" ]; then
		 [ -n "${__BASH_TIMING__-}" ] ||
			return 0
		local us=$(( ($(gettimeofday) / 1000) - $__BASH_TIMING__ ))
		if [ $us -gt 500000 ] || [  "$rc" != 0 ]; then
			local pair i
			for pair in 3600000000:h 60000000:m 1000000:s 1000:ms 0:us; do
				i="${pair%:*}"
				[ $us -gt $i ] ||
					continue
				printf '\033[1;31m%s\033[0m :: \033[1;33m' "$rc"
				[ $x != 0 ] &&
					printf "%g" "$(($us / $i)).$(($us / ($i / 100) % 100))" ||
					printf '%d' "$us"
				printf " %s\033[0m\n" "${pair#*:}"
				break
			done
		fi >&2
		__BASH_TIMING__=
	elif [ -z "${__BASH_TIMING__-}" ]; then
		__BASH_TIMING__=$(( $(gettimeofday) / 1000 ))
	fi
}

PROMPT_COMMAND="${PROMPT_COMMAND:-:}"
trap 'bash_timing' DEBUG